Thin layer chromatography (hereinafter also referred to as “TLC”) is known as a method for separating and detecting specific components in a mixture. When separating components by means of TLC, detection is achieved by subjecting spots, which are obtained by developing a sample, to irradiation with ultraviolet rays or to a coloration treatment using a coloring reagent on the basis of differences in optical responsiveness of, for example, a separating agent layer and the components being detected.
Meanwhile, separating agents that contain polysaccharide derivatives such as phenyl esters of polysaccharides are known as separating agents for optical isomers. When used in separating agent layers for TLC plates, such separating agents that contain aromatic rings are, in some cases, unable to detect components to be detected when irradiating with ultraviolet rays or carrying out coloration treatment using a coloring reagent.
As means for solving this type of problem, a TLC plate is known in which a first separating agent layer, which can achieve separation of target substances but does not exhibit an optical responsiveness, and a second separating agent layer, which does not achieve a separation function but exhibits an optical responsiveness, are formed side-by-side on the same substrate (for example, see patent document 1). In this TLC plate, target substances are developed from the first separating agent layer to the second separating agent layer, spots separated by the first separating agent layer migrate to the adjacent second separating agent layer and are detected there according to their optical responsiveness.
In this TLC plate, the extract component that is readily adsorbed by the first separating agent layer does not, in some cases, satisfactorily reach the second separating agent layer. In addition, because the speed of migration of a spot generally varies in each separating agent layer, the positional relationship of spots in a first separating agent layer is not necessarily precisely maintained in a second separating agent layer. Therefore, it is not necessarily possible to precisely detect the state of separation in the first separating agent layer in the aforementioned TLC plate, and further research is needed in this respect at least.
Patent Document 1: Japanese Patent No. 3140138